1. Field of the Invention
The present invention relates to an intermediate transfer belt for transferring a toner image formed on a photoconductor onto a transfer member, and an image forming device including the same.
2. Background Information
In a tandem-type color image forming device, a system is employed in which respective toner images formed on a photosensitive drum are superposed on an intermediate transfer belt, and the full color toner image formed thereby on the intermediate transfer belt is transferred onto a transfer member or transfer medium.
An intermediate transfer belt having multiple layers has been proposed in order to improve the transferability of toner images onto print media. The multilayered structure allows the intermediate transfer belt to conform to the surfaces of print media that are rough or textured.
As shown in FIG. 6, a conventional intermediate transfer belt 124 is comprised of a reinforcing layer 151 at the bottom, an elastic layer 152 in the middle, and a surface protective layer 153 at the top. The reinforcing layer 151 and the surface protective layer 153 comprise the surfaces of the intermediate transfer belt. The reinforcing layer 151 is comprised of a resin film, such as polyimide, preferably hard polyimide, or polyvinylidene fluoride (PVDF), for example. The elastic layer 152 could be made of nitrile rubber (NBR), silicone rubber, urethane, or other materials. The surface protective layer 153 could be coated with fluorocarbon polymers, Teflon™ resin, or other materials. Japan Patent Application Publication No. 10-39642 discloses a technique for determining the properties of the reinforcing layer 151 and the strength properties of the elastic layer 152 in a multilayered intermediate transfer belt.
The intermediate transfer belt 124 disclosed in Japan Patent Application Publication No. 10-39642 has a reinforcing layer 151 made of a high strength resin member, as well as an elastic layer 152 for improving transferability. However, one problem with the material of the elastic layer 152 is that the hardness thereof cannot be reduced to a significant degree, and the thickness thereof cannot be increased. If there are restrictions on the hardness and thickness thereof, then this will limits the extent to which the transferability of the intermediate transfer belts could be improved. In particular, when transferring images onto paper having a very rough or textured surface, good transfer will not be obtained if there are restrictions on the improvement in transferability.
In addition, Japan Unexamined Patent Publication No. 2002-49211 discloses that when a transfer belt is positioned around a fixing device, or when a thermal transfer system is employed, the temperature of the intermediate transfer belt 124 will change, thermal expansion of the intermediate transfer belt 124 will occur, and problems such as smearing of the color image will occur.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved intermediate transfer belt that is capable of improving the transfer performance to a transfer member, and capable preventing the smearing of color images from occurring if the temperature of the intermediate transfer belt is changed, as well as a need for an improved image forming device having the same. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.